scale query interval based on local clock offset. tested by many

not as efficient as I want it to be yet, but more is coming

src/usr.sbin/ntpd/client.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: client.c,v 1.19 2004/07/09 15:02:15 henning Exp $ */
+/*	$OpenBSD: client.c,v 1.20 2004/07/10 18:42:51 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -26,6 +26,8 @@
 
 #include "ntpd.h"
 
+int	client_update(struct ntp_peer *);
+
 int
 client_peer_init(struct ntp_peer *p)
 {
@@ -126,6 +128,8 @@ client_dispatch(struct ntp_peer *p)
 	ssize_t			 size;
 	struct ntp_msg		 msg;
 	double			 T1, T2, T3, T4;
+	double			 abs_offset;
+	time_t			 interval;
 
 	fsa_len = sizeof(fsa);
 	if ((size = recvfrom(p->query->fd, &buf, sizeof(buf), 0,
@@ -166,12 +170,26 @@ client_dispatch(struct ntp_peer *p)
 	p->reply[p->shift].good = 1;
 
 	if (p->trustlevel < TRUSTLEVEL_PATHETIC)
-		p->next = time(NULL) + INTERVAL_QUERY_PATHETIC;
+		interval = INTERVAL_QUERY_PATHETIC;
 	else if (p->trustlevel < TRUSTLEVEL_AGRESSIVE)
-		p->next = time(NULL) + INTERVAL_QUERY_AGRESSIVE;
-	else
-		p->next = time(NULL) + INTERVAL_QUERY_NORMAL;
+		interval = INTERVAL_QUERY_AGRESSIVE;
+	else {
+		if (p->update.offset < 0)
+			abs_offset = p->update.offset * -1;
+		else
+			abs_offset = p->update.offset;
+log_debug("offset %f, abs_offset %f", p->update.offset, abs_offset);
+		if (!p->update.good)
+			interval = INTERVAL_QUERY_NORMAL;
+		else if (abs_offset > QSCALE_OFF_MAX)
+			interval = INTERVAL_QUERY_NORMAL;
+		else if (abs_offset < QSCALE_OFF_MIN)
+			interval = INTERVAL_QUERY_NORMAL * (1 / QSCALE_OFF_MIN);
+		else
+			interval = INTERVAL_QUERY_NORMAL * (1 / abs_offset);
+	}
 
+	p->next = time(NULL) + interval;
 	p->deadline = 0;
 	p->state = STATE_REPLY_RECEIVED;
 
@@ -184,12 +202,55 @@ client_dispatch(struct ntp_peer *p)
 		p->trustlevel++;
 	}
 
-	log_debug("received reply from %s: offset %f delay %f",
-	    log_sockaddr((struct sockaddr *)&fsa), p->reply[p->shift].offset,
-	    p->reply[p->shift].delay);
+	log_debug("reply from %s: offset %f delay %f, "
+	    "next query %ds", log_sockaddr((struct sockaddr *)&fsa),
+	    p->reply[p->shift].offset, p->reply[p->shift].delay, interval);
 
-	if (++p->shift >= OFFSET_ARRAY_SIZE)
+	if (++p->shift >= OFFSET_ARRAY_SIZE) {
 		p->shift = 0;
+		client_update(p);
+	}
+
+	return (0);
+}
+
+int
+client_update(struct ntp_peer *p)
+{
+	int	i, best = 0, good = 0;
+
+	/*
+	 * clock filter
+	 * find the offset which arrived with the lowest delay
+	 * use that as the peer update
+	 * invalidate it and all older ones
+	 */
+
+	for (i = 0; good == 0 && i < OFFSET_ARRAY_SIZE; i++)
+		if (p->reply[i].good) {
+			good++;
+			best = i;
+		}
+
+	for (; i < OFFSET_ARRAY_SIZE; i++) {
+		if (p->reply[i].good &&
+		    p->reply[i].rcvd + REPLY_MAXAGE < time(NULL))
+			p->reply[i].good = 0;
+
+		if (p->reply[i].good)
+			good++;
+			if (p->reply[i].delay < p->reply[best].delay)
+				best = i;
+	}
+
+	if (good == 0)
+		return (-1);
+
+	memcpy(&p->update, &p->reply[best], sizeof(p->update));
+
+	for (i = 0; i < OFFSET_ARRAY_SIZE; i++)
+		if (p->reply[i].rcvd <= p->reply[best].rcvd)
+			p->reply[i].good = 0;
 
 	return (0);
 }

src/usr.sbin/ntpd/ntp.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.21 2004/07/09 15:00:43 henning Exp $ */
+/*	$OpenBSD: ntp.c,v 1.22 2004/07/10 18:42:51 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -38,7 +38,6 @@ struct l_fixedpt	 ref_ts;
 void	ntp_sighdlr(int);
 int	ntp_dispatch_imsg(void);
 void	ntp_adjtime(struct ntpd_conf *);
-int	get_peer_update(struct ntp_peer *, double *);
 
 void
 ntp_sighdlr(int sig)
@@ -175,7 +174,7 @@ ntp_main(int pipe_prnt[2], struct ntpd_conf *conf)
 				    log_sockaddr(
 				    (struct sockaddr *)&p->addr->ss));
 				if (p->trustlevel >= TRUSTLEVEL_BADPEER &&
-				    --p->trustlevel < TRUSTLEVEL_BADPEER)
+				    (p->trustlevel /= 2) < TRUSTLEVEL_BADPEER)
 					log_info("peer %s now invalid",
 					    log_sockaddr(
 					    (struct sockaddr *)&p->addr->ss));
@@ -278,13 +277,18 @@ void
 ntp_adjtime(struct ntpd_conf *conf)
 {
 	struct ntp_peer	*p;
-	double		 offset, offset_median = 0;
+	double		 offset_median = 0;
 	int		 offset_cnt = 0;
 
 	TAILQ_FOREACH(p, &conf->ntp_peers, entry)
-		if (get_peer_update(p, &offset) == 0) {
-			offset_median += offset;
-			offset_cnt++;
+		if (p->update.good) {
+			if (p->update.rcvd + REPLY_MAXAGE < time(NULL))
+				p->update.good = 0;
+			else
+				if (p->trustlevel >= TRUSTLEVEL_BADPEER) {
+					offset_median += p->update.offset;
+					offset_cnt++;
+				}
 		}
 
 	if (offset_cnt > 0) {
@@ -293,51 +297,3 @@ ntp_adjtime(struct ntpd_conf *conf)
 		    &offset_median, sizeof(offset_median));
 	}
 }
-
-int
-get_peer_update(struct ntp_peer *p, double *offset)
-{
-	int	i, best = 0, good = 0;
-
-	/*
-	 * clock filter
-	 * find the offset which arrived with the lowest delay
-	 * use that as the peer update
-	 * invalidate it and all older ones
-	 */
-
-	for (i = 0; good == 0 && i < OFFSET_ARRAY_SIZE; i++)
-		if (p->reply[i].good) {
-			good++;
-			best = i;
-		}
-
-	for (; i < OFFSET_ARRAY_SIZE; i++) {
-		if (p->reply[i].good &&
-		    p->reply[i].rcvd + REPLY_MAXAGE < time(NULL))
-			p->reply[i].good = 0;
-
-		if (p->reply[i].good)
-			good++;
-			if (p->reply[i].delay < p->reply[best].delay)
-				best = i;
-	}
-
-	/* lower trust in the peer when too few good replies received */
-	if (good < 8 && p->trustlevel > 0) {
-		if (p->trustlevel >= TRUSTLEVEL_BADPEER)
-			log_info("peer %s now invalid",
-			    log_sockaddr((struct sockaddr *)&p->addr->ss));
-		p->trustlevel /= 2;
-	}
-
-	if (good == 0 || p->trustlevel < TRUSTLEVEL_BADPEER)
-		return (-1);
-
-	for (i = 0; i < OFFSET_ARRAY_SIZE; i++)
-		if (p->reply[i].rcvd <= p->reply[best].rcvd)
-			p->reply[i].good = 0;
-
-	*offset = p->reply[best].offset;
-	return (0);
-}

src/usr.sbin/ntpd/ntpd.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.h,v 1.20 2004/07/09 19:44:18 deraadt Exp $ */
+/*	$OpenBSD: ntpd.h,v 1.21 2004/07/10 18:42:51 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -46,8 +46,11 @@
 #define	TRUSTLEVEL_PATHETIC		2
 #define	TRUSTLEVEL_AGRESSIVE		8
 
+#define	QSCALE_OFF_MIN			0.05
+#define	QSCALE_OFF_MAX			1
+
 #define	QUERYTIME_MAX		15	/* single query might take n secs max */
-#define	REPLY_MAXAGE		300
+#define	REPLY_MAXAGE		720
 #define	OFFSET_ARRAY_SIZE	8
 
 enum client_state {
@@ -84,6 +87,7 @@ struct ntp_peer {
 	time_t				 next;
 	time_t				 deadline;
 	struct ntp_offset		 reply[OFFSET_ARRAY_SIZE];
+	struct ntp_offset		 update;
 	u_int8_t			 shift;
 	u_int8_t			 trustlevel;
 };